ISO 11648-2 INTERNATIONAL STANDARD First edition 2001-10-15 Statistical aspects of sampling from bulk materials — Part 2: Sampling of particulate materials Aspects statistiques de l'échantillonnage des matériaux en vrac — Partie 2: Échantillonnage des matériaux particulaires Reference number ISO 11648-2:2001(E) © ISO 2001 `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) PDF disclaimer This PDF file may contain embedded typefaces In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy The ISO Central Secretariat accepts no liability in this area Adobe is a trademark of Adobe Systems Incorporated Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing Every care has been taken to ensure that the file is suitable for use by ISO member bodies In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below © ISO 2001 All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester ISO copyright office Case postale 56 · CH-1211 Geneva 20 Tel + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.ch Web www.iso.ch Printed in Switzerland `,,```,,,,````-`-`,,`,,`,`,,` - ii Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) Contents Page Foreword iv Introduction v Scope Normative references `,,```,,,,````-`-`,,`,,`,`,,` - Terms, definitions and symbols Applications of bulk material sampling 12 Principles of sampling 13 Establishing a sampling scheme .23 Mass of increment and minimization of bias 29 Number of increments .32 Masses of gross samples and sub-lot samples .34 10 Mass-basis sampling 40 11 Time-basis sampling 42 12 Stratified random sampling within fixed mass or time intervals 44 13 Mechanical sampling from moving streams 44 14 Manual sampling from moving streams 50 15 Stopped-belt sampling 51 16 Sampling from stationary situations 52 17 Principles of sample preparation .59 18 Precision of sample preparation 67 19 Bias in sample preparation .67 20 Preparation of samples for the determination of moisture .69 21 Preparation of samples for chemical analysis 71 22 Preparation of samples for physical testing 72 23 Precision and bias of measurement 72 24 Packing and marking of samples .73 Annex A (informative) Examples of variance calculations 74 Annex B (informative) Mechanical sampling implements 79 Annex C (informative) Manual sampling implements form moving streams 84 Annex D (informative) Sampling implements for stationary situations .86 Annex E (informative) Sample preparation schemes 89 Annex F (informative) Particle-size reduction equipment 91 Annex G (informative) Examples of mechanical mixers .94 Annex H (informative) Mechanical sample dividers 96 Annex I (informative) Implements for manual sample division 99 Annex J (informative) Examples of riffles 101 Bibliography 102 iii © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work of preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part Draft International Standards adopted by the technical committees are circulated to the member bodies for voting Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote Attention is drawn to the possibility that some of the elements of this part of ISO 11648 may be the subject of patent rights ISO shall not be held responsible for identifying any or all such patent rights International Standard ISO 11648-2 was prepared by Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 3, Application of statistical methods in standardization ISO 11648 consists of the following parts, under the general title Statistical aspects of sampling from bulk materials: ¾ Part 1: General principles ¾ Part 2: Sampling of particulate materials It is the intention of ISO/TC 69/SC to develop additional parts to ISO 11648 to cover the sampling of liquids and gases, if the need exists Annexes A to J of this part of ISO 11648 are for information only `,,```,,,,````-`-`,,`,,`,`,,` - iv Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) Introduction This part of ISO 11648 gives the basic methods for sampling bulk particulate materials in bulk (e.g ores, mineral concentrates, coal, industrial chemicals in powder and granular form, and agricultural products such as grain) from moving streams and stationary situations Part of ISO 11648 gives a broad outline of the statistical aspects of sampling from bulk materials `,,```,,,,````-`-`,,`,,`,`,,` - v © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 11648-2:2001(E) Statistical aspects of sampling from bulk materials — Part 2: Sampling of particulate materials Scope This part of ISO 11648 establishes the basic methods for sampling particulate materials in bulk (e.g ores, mineral concentrates, coal, industrial chemicals in powder or granular form, and agricultural products such as grain) from moving streams and stationary situations, including stopped-belt sampling, to provide samples for measuring one or more variables in an unbiased manner and with a known degree of precision The variables are measured by chemical analysis and/or physical testing These sampling methods are applicable to materials that require inspection to verify compliance with product specifications or contract settlements, to calculate the value of the lot mean of a measurable quantity as a basis for settlement between trading partners, or to estimate the set of variables and variances that describes a system or procedure Stopped-belt sampling is the reference method against which other sampling procedures are compared Dynamic sampling from moving streams is the preferred method whereby a sampling device (called a cutter) is passed through the stream of the particulate material A complete cross-section of the moving stream can be removed as a primary increment at a conveyor belt transfer point with a falling-stream cutter, or removed from the belt with a cross-belt cutter In both cases, the selection and extraction of increments can be described by a one-dimensional dynamic sampling model Static sampling of bulk material from stationary situations, such as stockpiles, rail or road wagons, the holds of ships and barges, silos, and even comparatively small volumes, is used only where sampling from moving streams is not possible Such sampling from three-dimensional lots is prone to systematic errors, because some parts of the lot usually have reduced or no chance of being collected for the gross sample This is in violation of the requirement of the three-dimensional sampling model that all parts have an equal probability of being collected The procedures described in this part of ISO 11648 for sampling from stationary lots of bulk particulate material with implements such as mechanical augers merely minimize some of the systematic sampling errors For these reasons, this part of ISO 11648 is primarily concerned with dynamic sampling from moving streams or stopped-belt static sampling from conveyor belts and is based on a sampling model for one-dimensional lots Nonetheless, procedures for static sampling from three-dimensional lots are provided where these situations cannot be avoided This part of ISO 11648 is concerned with the methods of sampling particulate materials in bulk with the objective of obtaining unbiased measurements of one or more variables of the material with a known degree of precision However, it does not provide methods for deciding whether to accept or reject a bulk material lot with specified degrees of risk of accepting a sub-standard lot, or of rejecting what is in fact an acceptable lot These latter procedures are usually called acceptance sampling or sampling inspection methods `,,```,,,,````-`-`,,`,,`,`,,` - © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 11648 For dated references, subsequent amendments to, or revisions of, any of these publications not apply However, parties to agreements based on this part of ISO 11648 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below For undated references, the latest edition of the normative document referred to applies Members of ISO and IEC maintain registers of currently valid International Standards ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes of openings ISO 3084, Iron ores — Experimental methods for evaluation of quality variation ISO 3085, Iron ores — Experimental methods for checking the precision of sampling ISO 3086, Iron ores — Experimental methods for checking the bias of sampling ISO 3534 (all parts), Statistics — Vocabulary and symbols ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 5725-3, Accuracy (trueness and precision) of measurement methods and results — Part 3: Intermediate measures of the precision of a standard measurement method ISO 5725-4, Accuracy (trueness and precision) of measurement methods and results — Part 4: Basic methods for the determination of the trueness of a standard measurement method ISO 5725-6, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice of accuracy values ISO 11648-1:—1), Statistical aspects of sampling from bulk materials — Part 1: General principles ISO 13909-7:—1), Hard coal and coke — Mechanical sampling — Part 7: Methods for determining the precision of sampling, sample preparation and testing ISO 13909-8:—1), Hard coal and coke — Mechanical sampling — Part 8: Methods of testing for bias Guide to the expression of uncertainty in measurement (GUM) BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, 1st edition, 1995 3.1 Terms, definitions and symbols Terms and definitions NOTE sampling 1) The text ábulk materialñ shown after terms means the definition given is confined to the field of bulk material To be published Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale `,,```,,,,````-`-`,,`,,`,`,,` - For the purpose of this part of ISO 11648, the terms and definitions of ISO 3534 (all parts) and the following (taken from the current draft revision of ISO 3534-2) apply ISO 11648-2:2001(E) 3.1.1 bulk material amount of material within which component parts are not initially distinguishable on the macroscopic level 3.1.2 sample ábulk materialñ subset of a specified population made up of one or more sampling units 3.1.3 sampling act of drawing or constituting a sample 3.1.4 simple random sampling sampling where a sample of n sampling units is taken from a population in such a way that all combinations of n sampling units have the same probability of being taken NOTE In bulk material sampling, if the sampling unit is an increment, the positioning, delimitation and extraction of increments should ensure that all sampling units have an equal probability of being selected 3.1.5 stratum mutually exclusive and exhaustive sub-population considered to be more homogeneous with respect to the characteristic investigated than the total population EXAMPLES In bulk material, strata, based on time, mass and space, are typically production periods (e.g 15 min), production masses (e.g 100 t), holds in vessels, wagons in a train, or containers 3.1.6 stratified sampling sampling such that portions of the sample are drawn from the different strata and each stratum is sampled with at least one sampling unit NOTE In some cases, the portions are specified proportions determined in advance However, in post-stratified sampling, the specified proportions would not be known in advance 3.1.7 stratified simple random sampling simple random sampling from each stratum 3.1.8 systematic sampling sampling according to a methodical scheme `,,```,,,,````-`-`,,`,,`,`,,` - NOTE In bulk sampling, systematic sampling may be achieved by taking items at fixed distances or after time intervals of fixed length Intervals may, for example, be on a mass or time basis In the case of a mass basis, sampling units or increments should be of equal mass With respect to a time basis, sampling units or increments should be taken from a moving stream or conveyor, for example, at uniform time intervals In this case, the mass of each sampling unit or increment should be proportional to the mass flow rate at the instant of taking the entity or increment NOTE If the lot is divided into strata, stratified systematic sampling can be carried out by taking increments at the same relative locations within each stratum 3.1.9 sampling unit ábulk materialñ one of the member parts, each with equal probability of selection in sampling, into which a population, comprised of the total quantity of bulk material under consideration, is divided NOTE In bulk sampling, the operative characteristics of the sampling unit are that the probability of selection of all sampling units should be equal and that the entire sampling unit becomes part of the sample when it is selected NOTE When sampling from a bulk material is performed by extraction of individual increments, the sampling unit is the primary increment © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) 3.1.10 precision closeness of agreement between independent test results obtained under stipulated conditions NOTE1 value Precision depends only on the distribution of random errors and does not relate to the true value or the specified NOTE The measure of precision is usually expressed in terms of imprecision and computed as a standard deviation of the test result Less precision is reflected by a larger standard deviation NOTE Quantitative measures of precision depend critically on the stipulated conditions Repeatability and reproducibility conditions are particular sets of extreme stipulated conditions 3.1.11 bias difference between the expectation of a test result and an accepted reference value NOTE Bias is the total systematic error as contrasted to random error There may be one or more systematic error components contributing to the bias A larger systematic difference from the accepted reference value is reflected by a larger bias value NOTE The bias of a measurement instrument is normally estimated by averaging the error of indication over an appropriate number of repeated measurements In this case, the error of indication is the “indication of a measuring instrument minus a true value of the corresponding input quantity” 3.1.12 lot ábulk materialñ definite part of a population, comprised of the total quantity of bulk material under consideration, and where this part is considered as a quantity of material for which specific characteristics are to be determined NOTE Commerce in bulk material often encompasses transactions involving single lots, and, in these cases, the lot becomes the population 3.1.13 sub-lot ábulk materialñ definite part of a lot of bulk material 3.1.14 increment ábulk materialñ quantity of bulk material taken in one action by a sampling device NOTE The positioning, delimitation and extraction of the increment should ensure that all parts of the bulk material in the lot have an equal probability of being selected NOTE Sampling is often carried out in progressive mechanical stages, in which case it is necessary to distinguish between a primary increment which is a sampling unit that is extracted from the lot at the first sampling stage, and a secondary increment which is extracted from the primary increment at the secondary sampling stage, and so on `,,```,,,,````-`-`,,`,,`,`,,` - 3.1.15 composite sample ábulk materialñ aggregation of two or more increments taken from a lot 3.1.16 gross sample ábulk materialñ aggregation of all the increments taken from a sub-lot or lot by the procedures of routine sampling 3.1.17 test sample ábulk materialñ sample, as prepared for testing or analysis, the whole quantity or a part of it being used for testing or analysis at one time Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale `,,```,,,,````-`-`,,`,,`,`,,` - ISO 11648-2:2001(E) Figure E.2 — Sample preparation from increments or sub-lot samples 90 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) Annexe F (informative) Particle-size reduction equipment `,,```,,,,````-`-`,,`,,`,`,,` - Typical equipment to reduce particle size is illustrated in Figures F.1 to F.4 Figure F.1 — Jaw crusher Figure F.2 — Roll crusher 91 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Key Rotating grinding plate Fixed grinding plate Hinged cover a View of plate detail Discharge b Figure F.3 — Plate mill `,,```,,,,````-`-`,,`,,`,`,,` - 92 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) `,,```,,,,````-`-`,,`,,`,`,,` - Key Top view of rings Rings Lid Toggle clamp Vibrating table NOTE Ring mill material is placed in the spaces between the loose rings, wall and centre disc Milling is induced by a vibrating table on which the milling chamber is clamped Figure F.4 — Ring mill 93 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Annexe G (informative) Examples of mechanical mixers Examples of mechanical mixers are illustrated in Figures G.1 and G.2 A double-cone mixer is shown in Figure G.1 and is suitable for mixing the residue from the first stage of sample division It has a short cylindrical portion, an inclined baffle plate and a closure plate at either end and is secured by bearings mounted on a suitable support The mixer rotates at approximately 60 r/min For quantities up to 0,25 kg, mixing for is sufficient, but for larger quantities, mixing for approximately is necessary Key Baffle plate Length: 400 mm Maximum diameter: 330 mm Figure G.1 — Double-cone mixer `,,```,,,,````-`-`,,`,,`,`,,` - 94 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) `,,```,,,,````-`-`,,`,,`,`,,` - Figure G.2 — V-style solids blender 95 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Annexe H (informative) Mechanical sample dividers Examples of mechanical sample dividers are illustrated in Figures H.1 and H.2 Figure H.1 — Rotating cone `,,```,,,,````-`-`,,`,,`,`,,` - 96 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) `,,```,,,,````-`-`,,`,,`,`,,` - Key Feed hopper Slide gate Vibratory feeder Removable canisters Turntable Drive (enclosed) Figure H.2 — An example of a rotary sample divider 97 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Figure H.3 — Rotating chute `,,```,,,,````-`-`,,`,,`,`,,` - 98 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) Annexe I (informative) Implements for manual sample division I.1 General This annex describes implements suitable for manual sample division I.2 Scoops A recommended design for a scoop is shown in Figure I.1 and the recommended dimensions are given in Table I.1 Scoops are not suitable for sampling bulk material with a nominal top size larger than about 45 mm Figure I.1 — Scoop Table I.1 — Recommended sizes of scoops `,,```,,,,````-`-`,,`,,`,`,,` - Nominal top size of material Minimum mass of increment Recommended dimensions mm kg mm L W H 75 35 30 110 50 40 170 70 50 31,5 220 95 80 45,0 300 135 120 11,2 16,0 22,4 Masses need to be determined; refer to 7.4 I.3 Shovels A recommended design of a shovel is shown in Figure I.2 with the recommended dimensions given in Table I.2 Shovels are not suitable for sampling bulk material with a nominal top size larger than about 63 mm 99 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Figure I.2 — Shovel Table I.2 — Recommended sizes of shovels Nominal top size of material Minimum mass of increment Recommended dimensions mm kg mm L W H 75 35 30 110 50 40 170 70 50 45,0 220 95 80 45,0 300 135 120 11,2 16,0 22,4 Masses need to be determined; refer to 7.4 `,,```,,,,````-`-`,,`,,`,`,,` - 100 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale ISO 11648-2:2001(E) Annexe J (informative) Examples of riffles `,,```,,,,````-`-`,,`,,`,`,,` - a) Open riffle b) Closed riffle Figure J.1 101 © ISO 2001 – All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) Bibliography [1] GY P.M Sampling of Heterogeneous and Dynamic Material Systems Elsevier Scientific Publishing, Amsterdam, 1992 [2] MERKS J.W Sampling and Weighing of Bulk Solids Trans Tech Publications, Clausthal-Zellerfield, Germany, 1st ed., 1985 [3] PITARD F.F Pierre Gy's Sampling Theory and Sampling Practice, CRC Press, Boca Raton, USA, 2nd ed., 1993 `,,```,,,,````-`-`,,`,,`,`,,` - 102 Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS © ISO 2001 – All rights reserved Not for Resale `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale ISO 11648-2:2001(E) ICS 03.120.30 Price based on 102 pages © ISO 2001 – All rights reserved `,,```,,,,````-`-`,,`,,`,`,,` - Copyright International Organization for Standardization Provided by IHS under license with ISO No reproduction or networking permitted without license from IHS Not for Resale